Dips, Sauces, & Custards, Side Dishes

Roasted Rainbow Potatoes with Mornay Sauce

Roasted rainbow potatoes with a mornay sauce is dish that I found intriguing.  Just after Thanksgiving, Busy Baker and I attended a very elegant outdoor wedding which served some dazzling food.  One of the items on the dinner buffet was a rainbow potato dish.  Since I enjoyed it, I hunted down the chef who was catering the event.  He told me he tossed the roasted potatoes in a bechamel sauce.  I thanked him, returned to my seat, and thought wouldn’t these roasted rainbow potatoes taste amazing if they were in a mornay sauce?  If you are a cheese lover, you might agree with me.

person holding a white bowl of roasted potatoes with mornay sauce

For this mornay sauce, I used gruyere cheese, which melts very well and tastes fantastic.  But wait–let’s back up.  Maybe I should explain what these two sauces are.  A bechamel sauce is one of the five mother sauces in French cooking.  It’s a basic sauce that is made from a roux and heated milk.  To change it to a mornay sauce all you need to do is add cheese.

spoonful of roasted rainbow potatoes with mornay sauce

Looking for more yummy potato recipes?  Pin these to save for later.

Crispy Baked Potato Wedges: an easy recipe for homemade russet potato wedges that are baked, not fried, to make them healthier! They’re a fantastic comfort food appetizer perfect for game day, Super Bowl, or the Olympics. | www.savortheflavour.com #superbowl #appetizer #gameday #potatoes #Olympics In this easy recipe for Buttery Garlic Parsley Potatoes, new red potatoes are boiled on the stovetop and tossed with brown butter, sautéed garlic, and fresh parsley to make the ultimate gluten free, comfort food side dish. | www.savortheflavour.com #poatotes #glutenfree #sidedish #parsley #comfortfood Traditional Irish Colcannon: a life-changing blend of creamy mashed potatoes with kale and green onions. It’s an easy, vegetarian side dish perfect for St. Patrick’s Day. | www.savortheflavour.com #stpatricksday #irish #colcannon #potatoes #kale

Crispy Baked Potato Wedges: an addicting appetizer perfect for game day or family gatherings.

Buttery Garlic Parsley Potatoes: a flavor-packed way to serve boiled potatoes.

Traditional Irish Colcannon: this life-changing recipe for Irish mashed potatoes will make you want seconds!

white bowl of roasted rainbow potatoes with mornay sauce

Roasted Rainbow Potatoes with Mornay Sauce

  • Author: Brooke
  • Prep Time: 15 minutes
  • Cook Time: 20 minutes
  • Total Time: 35 minutes
  • Yield: 8 servings


Roasted rainbow potatoes with mornay sauce are an easy vegetarian side dish with a gourmet twist that you can serve at your next elegant dinner party.  Crispy red, purple, and yellow baby potatoes are roasted with the skins on until crispy, then are tossed with a mornay sauce made with gruyere cheese and garnished with nutmeg.


For the Roasted Potatoes

  • 1 bag of rainbow baby potatoes (roughly 16)
  • glug of olive oil
  • sprinkle of salt

For the Mornay Sauce

  • 1 cup whole milk
  • 1 tablespoon unsalted butter
  • 2 tablespoons flour
  • 1/4 teaspoon salt
  • 1/8 teaspoon white pepper
  • 1/2 cup grated gruyere cheese (2.75 oz or 78g)

For Garnish

  • sprinkle of freshly grated nutmeg


Roasting the Potatoes

  1. Preheat the oven to 425F.
  2. Rinse the baby rainbow potatoes.  Quarter each potato and place in a large mixing bowl.
  3. Pour a glug of olive oil over top then mix well to coat each piece.
  4. Place on an oiled metal baking sheet.
  5. Bake for 10 minutes.  Flip the potatoes over and bake for another 10 minutes.  Check to see if it’s done by checking the color and poking a potato with a fork.  The potatoes should be soft on the inside and golden brown on the outside. If necessary, cook for another 5 minutes.

Making the Mornay Sauce

  1. Grate 1/2 cup of gruyere cheese.
  2. Heat the milk in a small saucepan over medium heat until it’s steaming.
  3. In a medium saucepan, melt the butter over medium low heat.  Gradually whisk in the flour to make a roux, then continue to whisk for another minute to cook the roux.
  4. Take the roux off the heat and slowly whisk in the heated milk, then continue to whisk until the mixture is smooth.
  5. Return the saucepan to low heat and whisk in the grated cheese.  Cook until the sauce reaches the desired thickness, whisking occasionally.
  6. Remove from the heat and season with salt, white pepper, and a pinch of freshly grated nutmeg.  Stir until well combined.
  7. Pour the mornay sauce over the roasted potatoes and toss to coat.  Garnish with more freshly grated nutmeg.  Serve immediately.

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